JP2012225527A - Defrosting control device of cooling storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a defrosting time.SOLUTION: A cooling storage in which a defrosting operation is performed during a cooling operation includes an all-day timer 32 which transmits a defrosting request signal, an operation condition detection portion 36 which detects the operation condition of a compressor 26, and an operation control portion 40 which starts the defrosting operation under conditions that the compressor 26 is in a halt condition and a storage interior temperature tr detected by a storage interior thermistor 30 reaches a predetermined value. If the defrosting request signal is transmitted and the timing thereof is in the operation of the compressor 26, the compressor 26 halts and then starts the defrosting operation after waiting for the storage interior temperature to reach the predetermined value. If the timing of the transmission of the defrosting request signal is in the halt of the compressor 26, the compressor starts the defrosting operation under the condition that the storage interior temperature has already reached the predetermined value. The defrosting operation is started when the temperature of a cooler 22 becomes high, thereby shortening the time required for subsequent defrosting.

Description

  The present invention relates to a defrost control device in a cooling storage.

  The thing described in the following patent document 1 is known as a prefabricated refrigerator which is an example of a cooling storage. In this, an indoor unit equipped with a cooler and a fan in the cabinet is arranged on the ceiling inside the cabinet, while a refrigeration apparatus comprising a compressor, an air-cooled condenser, etc. outside the cabinet An outdoor unit equipped with a refrigeration circuit is connected between the cooler and the refrigeration system by a refrigerant pipe, and a well-known refrigeration circuit is configured, and the internal temperature detected by the internal thermistor is When the predetermined internal set temperature is exceeded, the refrigeration system (compressor) and the internal fan are operated to circulate and supply cold air to the internal temperature, and the internal temperature is below the internal set temperature. By repeating at least the operation of the compressor being stopped, a cooling operation is performed in which the interior of the refrigerator is substantially maintained at the set temperature, and a defrosting operation is appropriately performed during the cooling operation. It is like that. Conventionally, the start of the defrosting operation is generally executed by a time-up signal such as an all-day timer.

JP 2010-216680 A

When the defrosting operation is started by the timer as described above, the defrosting is started regardless of the temperature of the cooler, that is, the cooling immediately after the compressor is stopped or immediately after the compressor is stopped. In some cases, the defrosting operation is started in a state where the cooler is cooled (for example, a state where the temperature is lower than the internal temperature by 5 to 10K or more). In the defrosting system, the heater driving power is consumed, and in the hot gas defrosting system that circulates hot gas to the cooler, the compressor driving power is consumed by the extra cooler. was there. Moreover, since the defrosting time also becomes long, the rising range of the inside temperature becomes large, and there is a concern that the food stored in the inside may be adversely affected.
Also, in the off-cycle defrosting method, defrosting is mainly performed by using the motor of the internal fan as a heat source, so it takes longer to defrost, and if the time is limited, the defrosting may not be completed. there were.
The present invention has been completed based on the above circumstances, and an object thereof is to shorten the defrosting time.

  The defrosting control device for a cooling storage of the present invention includes a cooler that is connected to a refrigeration device and generates heat by exchanging heat with the air in the storage, and the generated cold is circulated and supplied into the storage. An internal fan and an internal temperature sensor for detecting the internal temperature are provided, and when the internal temperature detected by the internal temperature sensor exceeds a predetermined internal temperature, the refrigeration apparatus and the internal storage When the internal fan is operated and the operation of the refrigeration apparatus is stopped at least when the internal temperature falls below the internal set temperature, a cooling operation is performed in which the internal temperature is substantially maintained at the internal set temperature, and this In a cooling storage where the defrosting operation is performed in the middle of the cooling operation, a signal sending unit for sending a defrost request signal and an operation state detection for detecting whether the refrigeration apparatus is in operation or stopped And the defrost request signal Since the refrigeration apparatus is in a stopped state and the internal temperature detected by the internal temperature sensor has reached a predetermined value, an operation control unit that starts a defrosting operation, It is characterized in that it is configured to include.

If a defrost request signal is issued and the timing is during operation of the refrigeration apparatus, the operation of the refrigeration apparatus is stopped, and after that, the defrost operation is started after waiting for the internal temperature to reach a predetermined value. . When the timing at which the defrost request signal is issued is when the refrigeration apparatus is stopped, the defrosting operation is started on the condition that the internal temperature has reached a predetermined value.
Since the temperature of the cooler is simulated by the internal temperature and the defrosting operation is started when the temperature of the cooler becomes high, the time required for the subsequent defrosting can be shortened, resulting in an increase in the internal temperature. Is kept small, and it is avoided that the food stored in the warehouse is adversely affected by heat.

  Moreover, the defrosting control device for a cooling storage according to another invention includes a cooler that is connected to the refrigeration device and generates heat by exchanging heat with the air in the storage, and the generated cold is stored in the storage. When the internal temperature detected by the internal temperature sensor exceeds a preset internal temperature, the refrigeration is performed. When the apparatus and the internal fan are operated, and the operation of the refrigeration apparatus is stopped at least when the internal temperature falls below the internal set temperature, a cooling operation is performed in which the internal temperature is substantially maintained at the internal set temperature. In the cooling storage where the defrosting operation is performed in the middle of the cooling operation, a signal sending unit for sending a defrost request signal and detecting whether the refrigeration apparatus is in operation or stopped Operating state detector A cooler temperature sensor for detecting a temperature of the cooler, a temperature difference calculating unit for calculating a difference between the temperature in the chamber detected by the temperature sensor in the chamber and the temperature of the cooler detected in the cooler temperature sensor; After the defrost request signal is sent, the defrosting operation is started on the condition that the refrigeration apparatus is in a stopped state and the temperature difference calculated by the temperature difference calculation unit is equal to or less than a predetermined value. The operation control unit is characterized in that the configuration is provided.

When the defrost request signal is issued and the timing is during operation of the refrigeration system, the operation of the refrigeration system is stopped, and after that, wait for the difference between the internal temperature and the cooler temperature to become a predetermined value or less. To start the defrosting operation. When the defrost request signal is issued when the refrigeration apparatus is stopped, the defrost operation is started on the condition that the difference between the internal temperature and the cooler temperature is equal to or less than a predetermined value.
It was considered that the temperature of the cooler was raised to some extent because the difference between the internal temperature and the cooler temperature was below a predetermined value, and the defrosting operation was started when the temperature of the cooler became higher in this way. Therefore, the time required for the subsequent defrosting can be shortened, and as a result, the increase in the internal temperature is suppressed to a small extent, and it is avoided that the food stored in the internal warehouse is adversely affected by heat.

Furthermore, it is good also as the following structures.
(1) The signal sending unit is a timer, and the defrost request signal is a time-up signal sent from the timer. The defrost request signal is automatically sent out by setting a time interval or the like in advance in the timer.
(2) The defrosting operation is performed by energizing the defrosting heater equipped in the cooler while the internal fan is stopped. In the case of heater defrosting, shortening the defrosting time can shorten the energization time to the defrosting heater and can also reduce power consumption.

(3) The defrosting operation is performed by stopping the internal fan and supplying hot gas to the cooler from a compressor constituting the refrigeration apparatus. In the case of hot gas defrosting, the driving time of the hot gas supply compressor can be shortened by reducing the defrosting time, and the power consumption can also be suppressed.
(4) The defrosting operation is an off-cycle defrosting in which the operation of the internal fan is continued while the refrigeration apparatus is stopped. It can also be applied to off-cycle defrosting.

  According to the present invention, the defrosting time can be shortened.

Partially cutaway perspective view of a prefabricated refrigerator according to Embodiment 1 of the present invention Same part cutaway front view Schematic cross section of indoor unit Block diagram of defrost control mechanism Flow chart of defrost control Same timing chart The block diagram of the defrost control mechanism part which concerns on Embodiment 2. FIG. Flow chart of defrost control Same timing chart Timing chart of related technology 1 defrost control Timing chart for heater defrosting according to Related Technology 2 Timing chart when performing off-cycle defrosting Timing chart for determining whether heater defrosting is necessary after skipping the defrosting

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the case where it applies to a prefabricated refrigerator is illustrated.
As shown in FIGS. 1 and 2, the prefabricated refrigerator 10 of this embodiment includes a refrigerator main body 11 formed into a square box shape by assembling a plurality of heat insulating panels, and the inside is a storage room. 12 and a heat insulating door 13 is mounted on the front face so as to be swingable.
As will be described later, an indoor unit 15 equipped with a cooler 22 (evaporator) and an internal fan 23 is disposed on the ceiling of the storage chamber 12, while a compression is provided outside the main body 11. An outdoor unit 25 equipped with a refrigerator 26 (see FIG. 4), a refrigeration apparatus including an air-cooled condenser, and the like is installed. A refrigeration circuit is configured.

  The indoor unit 15 includes a casing 16 that is elongated in the depth direction in the storage chamber 12, and as shown in FIG. 3, a suction port 17 is formed over substantially the entire rear surface (the right surface in the figure), and a mesh guard. On the other hand, a plurality of air outlets 20 made of bell mouths are formed on the front surface. A cooler 22 is arranged inside the suction port 17 in the casing 16, and an internal fan 23 made of a fan motor is arranged at each outlet 20.

Moreover, the defrost heater 27 which consists of a sheathed heater is mounted | worn with the back surface used as the suction surface in the cooler 22, and a lower surface for the defrost operation.
The bottom surface of the casing 16 is a drain pan 28, which is formed in a slanted shape with a downward slope toward the rear (the right side in FIG. 3), and a drain pipe 29 is connected to a drain port 28 </ b> A provided at the lower edge thereof. It is erected and led outside the warehouse.

  The cooling operation is performed by driving the refrigeration apparatus (compressor 26) and the internal fan 23, and as shown by the arrow in FIG. While the air flows forward through the cooler 22, cold air is generated by heat exchange, and a circulating flow is generated in which the cold air is blown out from the blower outlet 20 along the ceiling surface. Is cooled. During this time, the temperature tr in the storage chamber 12 detected by the in-compartment thermistor 30 provided in the guard 18 stretched at the suction port 17 is a predetermined lower limit value ts_off (compressor OFF temperature) of the in-compartment set temperature ts. ), The compressor 26 is stopped (the internal fan 23 is continuously operated), and conversely, the temperature in the storage chamber 12 is higher than the upper limit value ts_on (compressor ON temperature) of the internal set temperature ts. When it becomes higher, the compressor 26 is repeatedly driven, and the inside of the storage chamber 12 is maintained substantially at the internal set temperature ts.

A defrosting operation is performed during the cooling operation. The defrosting operation is performed, for example, every 3 hours based on the all-day timer 32 (see FIG. 4). As will be described in detail later, with the compressor 26 and the internal fan 23 stopped, the defrosting heater 27 is stopped. The defrost water is received by the drain pan 28 and then flows down the drain pipe 29 and is drained outside the warehouse.
The defrosting thermistor 34 for detecting the temperature of the cooler 22 is attached to, for example, the end plate of the cooler 22. During the defrosting operation, the detected temperature te of the defrosting thermistor 34, that is, the temperature of the cooler 22. When the temperature reaches a predetermined temperature (defrosting completion temperature), it is considered that frosting has disappeared, and the defrosting operation is terminated.

In the present embodiment, a device is devised for determining the timing of the above-described defrosting operation control, particularly the start timing of the defrosting operation, which will be described below.
As shown in FIG. 4, the control mechanism unit is provided with an operation control unit 40 that stores a microcomputer or the like and executes a predetermined program. On the input side, the all-day timer 32, the internal thermistor 30, In addition to the defrosting thermistor 34, an operating state detector 36 that detects whether the compressor 26 is in an operating state or in a stopped state is connected. A compressor 26, an internal fan 23, and a defrost heater 27 are connected to the output side.

  More specifically, the operation control unit 40 is provided with a temperature determination unit 41 and a defrost command unit 42, and the temperature determination unit 41 is configured such that the detected temperature tr of the internal thermistor 30 has a predetermined value a (inside the internal storage). It functions to determine whether or not the temperature is equal to or higher than the set temperature (ts) and to output a corresponding signal, and the defrost command unit 42 detects that the compressor 26 is in a stopped state from the operation state detection unit 36 described above. When a signal is obtained and a determination signal that the detected temperature tr of the internal thermistor 30 is equal to or higher than the predetermined value a is obtained from the temperature determination unit 41, the defrosting start command signal is output. When a defrost start command signal is sent, the operation of the compressor 26 and the internal fan 23 is stopped (or the operation stop is continued), and the defrost heater 27 is energized.

Next, an example of the operation of the present embodiment will be described with reference to the flowchart of FIG. 5 and the timing chart of FIG.
While the cooling operation is being executed, when the all-day timer 32 times out (step S10 is “Yes”), that is, when a defrost request signal is issued, whether or not the compressor 26 is in an operating state in step S11. Is detected and the compressor 26 is in an operating state (step S11 is “Yes” / timing T1), the cooling operation is continued. After that, when the compressor 26 is stopped by detecting that the internal temperature tr reaches the OFF temperature ts_off of the internal set temperature ts (step S11 is “No”), in step S12, the internal thermistor It is detected whether or not the internal temperature tr detected at 30 is equal to or higher than a predetermined value a (= internal set temperature ts), and when the internal temperature tr reaches the predetermined value a after a lapse of time (step S12 is “ In step S13, a defrost start command signal is issued (timing Ts).

  Further, when the timing at which the defrost request signal is issued ("Yes" at step S10) is that the compressor 26 is in a stopped state ("No" at step S11 / timing T2), subsequently, in step S12, It is detected whether or not the temperature tr is equal to or higher than the predetermined value a. If it is still lower than the predetermined value a (“No” in step S12), the internal temperature tr reaches the predetermined value a after a lapse of time (step S12). Is "Yes", a defrost start command signal is issued in step S13 (timing Ts) If the internal temperature tr has already reached the predetermined value a when the process proceeds to step S12 (step S12 In step S13, a defrost start command signal is immediately issued.

When the defrost start command signal is issued, the compressor 26 is continuously stopped, the operation of the internal fan 23 is stopped, and the defrost heater 27 is energized to start the defrost operation. The
After the start of the defrosting operation, when the detection temperature of the defrosting thermistor 34 equipped in the cooler 22 reaches the defrosting completion temperature, the energization to the defrosting heater 27 is finished, that is, the defrosting operation is performed. finish. After that, the cooling operation is resumed.

As described above, according to the present embodiment, the temperature of the cooler 22 is simulated by the internal temperature, and the defrost operation is started when the temperature of the cooler 22 becomes high regardless of the timing when the defrost request is issued. Therefore, the time required for the subsequent defrosting can be shortened.
Therefore, the increase range of the internal temperature can be suppressed to be small, and the adverse thermal effect on the stored food in the internal storage can be suppressed, and the energization time to the defrosting heater 27 can be shortened to reduce the power consumption. Can do.
Originally, the frost melted by the defrost heater 27 in the defrosting operation can be used as an energy source for internal cooling until the internal temperature (temperature of the cooler 22) rises to some extent. In other words, the operation is efficient.
Since the temperature of the cooler 22 is simulated by the internal temperature detected by the existing internal thermistor 30, a structural additional member is unnecessary and can be provided at low cost.

<Modification 1>
As the defrosting method, a hot gas defrosting method may be adopted instead of the heater defrosting method described above.
In the case of the hot gas defrosting method, when the defrosting start command signal is issued (timing Ts) in the timing chart of FIG. While being driven, the refrigerant pipe is switched and hot gas is supplied from the compressor 26 to the cooler 22 to perform defrosting.
This hot gas defrosting method is effective in reducing the operation time of the compressor 26 for defrosting as the time required for defrosting is shortened, and thus reducing the power consumption. In addition, the same effects as those of the first embodiment can be obtained.

<Modification 2>
You may employ | adopt an off-cycle defrost system as a defrost system further.
In the case of the off-cycle defrosting method, in the timing chart of FIG. 6, when the defrosting start command signal is issued (timing Ts), the compressor 26 continues to be stopped and the internal fan 23 As shown in the chain line chart y, the internal fan 23 is in an operating state. The frost formation of the cooler 22 is melted mainly using the heat generated by the motor accompanying the operation of the internal fan 23 as a heat source. In the case of off-cycle defrosting, a defrosting operation is performed for a fixed time by a timer.
Also in this off-cycle defrosting method, since the defrosting operation is started from the point where the temperature of the cooler 22 is also increased, the set time for performing the necessary defrosting can be shortened. The increase range of the internal temperature can be suppressed small, and the thermal adverse effect on the stored food in the internal storage can be suppressed.

In addition, in the first embodiment including the first and second modified examples, in order to see the temperature of the cooler 22, the temperature of the cooler 22 is not actually detected, but the internal temperature is detected and simulated. The reason for this is as follows.
When the temperature of the cooler 22 is directly detected, the refrigeration capacity varies depending on the season (the refrigeration capacity increases in the winter), so the temperature of the cooler 22 when the operation of the compressor 26 is stopped also varies depending on the season. Differently, the time until the temperature of the cooler 22 rises and reaches a predetermined temperature (starting temperature of the defrosting operation) is also different. As a result, the range of rise in the internal temperature also changes, and the optimum predetermined temperature differs depending on the season, making it difficult to set an appropriate predetermined temperature.

  For example, in a refrigerator that employs an off-cycle defrosting method, if the predetermined temperature is not properly set in summer when the internal set temperature ts is set to a low temperature such as “0 ° C.”, the off-cycle defrosting is not performed. Therefore, the temperature rise of the cooler 22 is slow, but the internal temperature rises relatively quickly, so that the internal temperature tr reaches the internal set temperature ts before the cooler temperature te reaches the predetermined temperature. After that, when the cooler temperature te reaches the predetermined temperature and the off-cycle defrosting is performed again for a certain period of time, the increase in the internal temperature becomes considerably large, and the stored food is thermally adversely affected. There is a risk.

On the other hand, when the internal temperature tr is detected as in the first embodiment, the internal temperature ts is adjusted within a relatively narrow temperature range regardless of the season. Even if the optimum predetermined temperature (starting temperature of defrosting operation) cannot be set, at least it can be set to an appropriate temperature under the premise that it does not adversely affect the stored food. Control that fully considers proper storage can be realized.
In addition, this control that applies means for imitating the temperature of the cooler 22 by the internal temperature tr can be applied to any defrosting method of the heater defrosting method, the hot gas defrosting method, and the off-cycle defrosting method. In addition, it is also possible to apply to a type in which the end of defrosting is controlled by a timer, that is, a type that does not include a defrosting thermistor 34 that detects the temperature of the cooler 22.

When the compressor is stopped, a timer is started, and defrosting is started when the timer detects that a predetermined time (a time when the temperature of the cooler is expected to rise to some extent) has elapsed. It is also possible. However, in this case, depending on the season, it is necessary to set the time short because the temperature rises quickly in summer, while in winter, the temperature rises slowly, so if the time is not lengthened, the optimal timing (cooler temperature When it rises to some extent). In order to prevent the food from being adversely affected by heat, the time should be set according to the summertime. In this case, the time is short. The temperature does not rise sufficiently. Conversely, if the time is set according to the winter season, the storage temperature will rise too much in the summer, and the stored food will be adversely affected. Therefore, when performing time control, it is necessary to re-set the time depending on the season, or to take measures to automatically change the time setting by detecting an external factor with an outside air temperature sensor or the like.
In the temperature control system according to the first embodiment, the above-described operational trouble can be saved, and the control system including the members can be simplified.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. In this Embodiment 2, the change is added to the control form of the part which determines the timing of a defrost operation start.
In the operation control unit 40A of the second embodiment, as shown in FIG. 7, a temperature difference calculation unit 44 and a temperature difference determination unit 45 are provided instead of the temperature determination unit 41 shown in the first embodiment. The temperature difference calculation unit 44 functions to calculate a temperature difference Δt between the internal temperature tr detected by the internal thermistor 30 and the cooler temperature te detected by the defrosting thermistor 34. The temperature difference determination unit 45 functions to determine whether or not the calculated value Δt is equal to or less than a predetermined value α and to output a corresponding determination signal.

  The defrosting instruction unit 42A obtains a detection signal indicating that the compressor 26 is in a stopped state from the operation state detection unit 36, and the temperature difference determination unit 45 determines the temperature between the internal temperature tr and the cooler temperature te. When a determination signal indicating that the difference Δt is equal to or less than the predetermined value α is obtained, it functions to issue a defrost start command signal. When the command signal for starting the defrosting is sent, the operation of the compressor 26 and the internal fan 23 is stopped (or the operation stop is continued) and the defrosting heater 27 is energized, as in the first embodiment. It is like that.

An example of the operation of the second embodiment will be described with reference to the flowchart of FIG. 8 and the timing chart of FIG.
While the cooling operation is being executed, when the all-day timer 32 times out ("Yes" in step S20), that is, when a defrost request signal is issued, whether or not the compressor 26 is in an operating state in step S21. Is detected and the compressor 26 is in the operating state (step S21 is “Yes” / timing T1), the cooling operation is continued. After that, when the compressor 26 is stopped by detecting that the internal temperature tr reaches the OFF temperature ts_off of the internal set temperature ts (step S21 is “No”), in step S22, the internal thermistor Whether or not the temperature difference Δt between the internal temperature tr detected at 30 and the cooler temperature te detected by the defrosting thermistor 34 is equal to or less than a predetermined value α {tr−te (= Δt) ≦ α}. When the temperature difference Δt is detected and the temperature difference Δt has decreased to a predetermined value α after a lapse of time (“Yes” in step S22), a defrosting start command signal is issued in step S23 (timing Ts).

  Further, when the timing at which the defrost request signal is issued ("Yes" at step S20) is when the compressor 26 is in a stopped state ("No" at step S21 / timing T2), subsequently, in step S22, It is detected whether or not the temperature difference Δt between the temperature tr and the cooler temperature te is equal to or less than the predetermined value α. If the temperature difference Δt still exceeds the predetermined value α (“No” in step S22), the internal temperature tr and the cooling after the elapse of time. When the temperature difference Δt of the vessel temperature te reaches a predetermined value α (“Yes” in step S22), a defrost start command signal is issued in step S23 (timing Ts). When the process proceeds to step S22, if the temperature difference Δt between the internal temperature tr and the cooler temperature te is already equal to or less than the predetermined value α (step S22 is “Yes”), the defrosting start is immediately started in step S23. A command signal is issued.

When the defrost start command signal is issued, the compressor 26 is continuously stopped, the operation of the internal fan 23 is stopped, and the defrost heater 27 is energized to start the defrost operation. The
After the start of the defrosting operation, when the detection temperature of the defrosting thermistor 34 equipped in the cooler 22 reaches the defrosting completion temperature, the energization to the defrosting heater 27 is finished, that is, the defrosting operation is performed. finish. After that, the cooling operation is resumed.

  According to the present embodiment, it is considered that the temperature of the cooler 22 has increased to some extent because the difference Δt between the internal temperature tr and the cooler temperature te is equal to or less than the predetermined value α, and thus the temperature of the cooler 22 is Since the defrosting operation is started when it becomes higher, the time required for the subsequent defrosting can be shortened. Therefore, the increase range of the internal temperature can be suppressed to be small, and the adverse thermal effect on the stored food in the internal storage can be suppressed, and the energization time to the defrosting heater 27 can be shortened to reduce the power consumption. Can do.

In the second embodiment, as a condition for issuing a defrosting operation command signal on the assumption that the temperature of the cooler 22 has increased to some extent, the difference Δt between the internal temperature tr and the cooler temperature te is a predetermined value α or less. The reason is as follows.
In the first embodiment, the temperature of the cooler 22 is simulated by the internal temperature. However, when the cooler temperature and the internal temperature are not closely linked, for example, the material of the cooler 22 and the compressor 26 are used. The temperature rise rate of the cooler 22 may be slow depending on the model due to various factors such as the operation mode of the internal fan 23 during the stop and the heat insulation of the cooler room (indoor unit 15). It differs depending on external factors. In short, in the situation where the internal temperature has risen relatively quickly but the cooler temperature has not risen much, it is not very effective in reducing the defrosting time.
In this respect, in the second embodiment, since the cooler temperature is added to the condition elements in addition to the internal temperature, the cooling is performed even when an external factor is added regardless of the model having various factors. The possibility that a command signal for the defrosting operation can be issued when the temperature of the vessel 22 becomes high, and the effect that the defrosting time can be shortened can be more reliably exhibited.

<Modification 1>
As a first modification of the second embodiment, a hot gas defrosting method may be adopted instead of the heater defrosting method.
In the case of the hot gas defrosting method, when the defrosting start command signal is issued in the timing chart of FIG. 9, the compressor 26 is driven as shown in the chain line chart xa of the compressor 26. The refrigerant pipe is switched and hot gas is supplied from the compressor 26 to the cooler 22 to perform defrosting.
In the hot gas defrosting method, the operation time of the compressor 26 for defrosting can be shortened as the time required for defrosting is shortened, and it is effective for suppressing power consumption. In addition, the same effects as those of the second embodiment can be obtained.

<Modification 2>
As Modification 2, an off-cycle defrosting method may be employed.
In the case of the off-cycle defrosting method, in the timing chart of FIG. 9, when the defrosting start command signal is issued, the compressor 26 continues to be stopped and the chain line chart ya of the internal fan 23 As shown in FIG. 3, the internal fan 23 is in an operating state. The frosting of the cooler 22 is mainly melted by the internal fan 23 using the heat generated by the motor during operation as a heat source. In the case of off-cycle defrosting, a defrosting operation is performed for a fixed time by a timer.
Also in this off-cycle defrosting method, since the defrosting operation is started from the point where the temperature of the cooler 22 is also increased, the set time for performing the necessary defrosting can be shortened. The increase range of the internal temperature can be suppressed small, and the thermal adverse effect on the stored food in the internal storage can be suppressed.

<Related technology 1>
FIG. 10 shows Related Technique 1. In this related technique 1, defrosting control using both off-cycle defrosting and heater defrosting is exemplified as one form of defrosting operation. In addition, about each member, the same thing as Embodiment 1 attaches | subjects and demonstrates the same code | symbol.
Describing according to the timing chart of FIG. 10, during the cooling operation, when the all-day timer 32 times out, the defrosting operation is not started immediately, but in the first compressor stop state after the time up, When the internal temperature tr detected by the internal thermistor 30 becomes equal to or higher than the internal set temperature ts (timing T10), off-cycle defrosting is started. The off-cycle defrosting ends when the end condition is detected, for example, when the cooler temperature reaches a predetermined temperature or when the backup timer times out.

When the off-cycle defrosting is finished, if the difference Δt1 between the internal temperature tr detected by the internal thermistor 30 and the cooler temperature te detected by the defrost thermistor 34 is a predetermined value β, that is,
Internal temperature tr−cooler temperature te (= Δt1) ≧ β (β: any integer value such as 2K, 3K)
When the relationship is established, it is determined that the frost formation of the cooler 22 has not been completely removed.
When the condition of the above equation is satisfied, the operation of the internal fan 23 is stopped and the defrost heater 27 is energized to start the heater defrost operation. After the start of the defrosting operation, the defrosting operation ends when the detected temperature te of the defrosting thermistor 34 reaches the defrosting completion temperature. After that, the cooling operation is resumed.

If the defrosting is not partitioned by off-cycle defrosting, it is covered with heater defrosting. Since the basic defrosting method is off-cycle defrosting, power consumption is reduced and energy saving is achieved. In addition, reliable defrosting can be expected.
Note that hot gas defrosting may be employed instead of the heater defrosting.

<Related technology 2>
11 to 13 show Related Art 2. This related technique 2 illustrates a case where off-cycle defrosting and heater defrosting are selected and executed at the start of the defrosting operation. Similarly, the same members as those in the first embodiment will be described with the same reference numerals.
While the cooling operation is being performed, if the all-day timer 32 times out, the defrosting operation is not started immediately, but the inside of the compartment detected by the inside thermistor 30 in the first compressor stop state after the time up. When the temperature tr becomes equal to or higher than the internal set temperature ts (timing T20), the defrosting operation is started.

At the operation start timing, the difference between the internal temperature tr detected by the internal thermistor 30 and the cooler temperature te detected by the defrosting thermistor 34 is calculated,
(1) Internal temperature tr-cooler temperature te (= Δt2) ≧ γ (γ: any integer value such as 2K, 3K)
In this case, heater defrosting is applied as shown in FIG.
(2) 0 <Internal temperature tr−Cooler temperature te (= Δt2) <γ
In this case, off-cycle defrosting is applied as shown in FIG.
(3) Internal temperature tr−Cooler temperature te (= Δt2) <0
In this case, the defrosting operation is skipped as shown in FIG.

The end conditions of the heater defrosting and off-cycle defrosting are when the cooler temperature reaches a predetermined temperature or when the backup timer times out. Note that the cooler temperature and the time-up time may be different between the two.
In the case of the result shown in (3) above, as shown in FIG. 13, the defrosting operation is once skipped, but after the compressor 26 is stopped again during the cooling operation, the internal temperature tr is When the internal set temperature ts is reached (timing T21), the defrosting operation is determined again based on the difference Δt2 between the internal temperature tr and the cooler temperature te. If the determination is the start of defrosting, heater defrosting or off-cycle defrosting is performed, and if the determination is skipping defrosting, the cooling operation is continued without performing defrosting.

Since an appropriate defrosting method is always selected at the timing of starting the defrosting operation, power consumption can be suppressed while ensuring defrosting.
The optimum defrosting method is selected in accordance with the use conditions by appropriately changing the predetermined value γ compared with the temperature difference Δt2 between the internal temperature tr and the cooler temperature te used when selecting the defrosting method. It becomes possible.
As exemplified in (3) above, when it is determined that there is no frost formation, the defrosting is skipped, that is, the increase in the internal temperature is suppressed by avoiding excessive defrosting. Thermal adverse effects can also be avoided.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above-described embodiment, the case where a timer such as an all-day timer is applied as the signal transmission unit that transmits the defrost request signal is exemplified. However, the frost detection signal detected by the frost detection means or manually The defrost request signal may be transmitted based on other signals such as an operation signal of the defrost operation button.
(2) In the first embodiment, the predetermined value to be compared with the internal temperature detected by the internal thermistor so as to prompt the start of defrosting is not limited to the internal set temperature, and may be another temperature.

(3) The prefabricated refrigerator has a large interior, and therefore the prefabricated refrigerator of the above embodiment can be operated by operating the internal fan regardless of the operation state of the compressor during the cooling control operation. However, the internal fan may be intermittently operated when the compressor is turned off.
(4) The present invention is not limited to the prefabricated refrigerators exemplified in the above embodiment, and can be applied to general cooling storages having a defrosting operation function such as commercial refrigerators and freezers.

  DESCRIPTION OF SYMBOLS 10 ... Prefabricated refrigerator (cooling storage) 11 ... Refrigerator main body (storage main body) 12 ... Storage room 22 ... Cooler 23 ... In-compartment fan 26 ... Compressor (refrigeration device) 27 ... Defrost heater 30 ... In-thermistor (inside of storage) Temperature sensor) 32 ... All-day timer (signal sending unit) 34 ... Defrosting thermistor (cooler temperature sensor) 36 ... Operating state detection unit 40, 40A ... Operation control unit 41 ... Temperature determination unit 42, 42A ... Defrosting command unit 44 ... Temperature difference calculator 45 ... Temperature difference determiner

Claims (6)

In the storage, a cooler that is connected to a refrigeration system and generates heat by exchanging heat with the air in the storage, an internal fan that circulates the generated cold into the storage, and a storage that detects the internal temperature. An internal temperature sensor,
When the internal temperature detected by the internal temperature sensor exceeds a predetermined internal set temperature, the refrigeration apparatus and the internal fan are operated, and when the internal temperature is below the internal set temperature, at least the operation of the freezing apparatus is performed. In the cooling storehouse in which the cooling operation is performed so that the inside of the warehouse is substantially maintained at the set temperature inside the warehouse, and the defrosting operation is performed in the middle of the cooling operation, by repeatedly stopping
A signal sending unit for sending a defrost request signal;
An operation state detection unit that detects whether the refrigeration apparatus is in an operation state or a stop state; and
After the defrost request signal is sent, the defrosting operation is started on the condition that the refrigeration apparatus is in a stopped state and the internal temperature detected by the internal temperature sensor has reached a predetermined value. An operation control unit;
A defrosting control device for a cooling storage, comprising: In the storage, a cooler that is connected to a refrigeration system and generates heat by exchanging heat with the air in the storage, an internal fan that circulates the generated cold into the storage, and a storage that detects the internal temperature. An internal temperature sensor,
When the internal temperature detected by the internal temperature sensor exceeds a predetermined internal set temperature, the refrigeration apparatus and the internal fan are operated, and when the internal temperature is below the internal set temperature, at least the operation of the freezing apparatus is performed. In the cooling storehouse in which the cooling operation is performed so that the inside of the warehouse is substantially maintained at the set temperature inside the warehouse, and the defrosting operation is performed in the middle of the cooling operation, by repeatedly stopping
A signal sending unit for sending a defrost request signal;
An operation state detection unit that detects whether the refrigeration apparatus is in an operation state or a stop state; and
A cooler temperature sensor for detecting the temperature of the cooler;
A temperature difference calculation unit that calculates a difference between the internal temperature detected by the internal temperature sensor and the cooler temperature detected by the cooler temperature sensor;
An operation for starting the defrosting operation on condition that the refrigeration apparatus is in a stopped state and the temperature difference calculated by the temperature difference calculation unit becomes a predetermined value or less after the defrost request signal is sent. A control unit;
A defrosting control device for a cooling storage, comprising: The defrosting control device for a cooling storage according to claim 1 or 2, wherein the signal sending unit is a timer, and the defrosting request signal is a time-up signal sent from the timer. The defrosting operation is performed by energizing a defrosting heater equipped in the cooler while the internal fan is stopped. The defrost control device for the cooling storage according to item. 2. The defrosting operation is performed by stopping hot air in the refrigerator and supplying hot gas from a compressor constituting the refrigeration apparatus to the cooler. The defrost control apparatus of the cooling storage as described in any one of thru | or 3 thru | or 3. The cooling according to any one of claims 1 to 3, wherein the defrosting operation is an off-cycle defrosting in which the operation of the internal fan is continued while the refrigeration apparatus is stopped. Storage defrost control device.

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